The 28-year-old striker moved to the Nou Camp this week from Atletico Madrid after the Catalan giants finally met his £107million buy-out clause.
He was unveiled at the club's stadium at a press conference on Sunday evening and the France international spoke about his intention to make an impact at Barcelona.
Then when asked about having Messi, a five-time Ballon d'Or winner, as a team-mate, Griezmann revealed his excitement at playing alongside the legend.
"I'm very happy. It's a joy for me to play alongside him," he said. "He is the number one player for me, like Lebron James in the NBA.
"He is someone that every player can look up to, and he will be a legend to my children - and my children's children in the future."